Electrical wiring devices are installed in various types of installations, for example, industrial, residential and commercial applications and settings. The appearance and safety of the electrical wiring device is greatly enhanced by the wall plate. The wall plates are typically connected to the wiring device by screws which may not provide the desired aesthetics depending on the intended use. The installation of the wall plate typically involves small screws that can be easily dropped or lost.
Wiring devices such as a switch or electrical receptacle are typically mounted in an electrical box which is in turn mounted to a wall stud or other support structure. The open end of the electrical box is usually mounted flush with the outer surface of the wall. A cover plate or face plate is attached to the electrical device to cover the open end of the electrical box and to provide a decorative appearance. Face plates are typically attached by one or more screws that extend through a screw hole in the face plate and are threaded into the electrical device.
Various face plates have been produced having no visible screws or fasteners on the outer surface. The face plates typically have a snap mechanism that enables the attachment of the face plate to an adapter plate or some intermediate plate that must be first attached to the wiring device. One example is disclosed in U.S. Pat. No. 5,723,817 to Arenas et al. This cover plate assembly is suitable for single gang or multi gang boxes. The device includes an attachment plate having a tab at each end. A face plate is snapped onto the tabs to attach the face plate to the attachment plate.
Another example of a faceplate attachment assembly is disclosed in U.S. Pat. No. 5,189,259 to Carson et al. The face plate assembly includes a mounting plate having a hook-like portion. A face plate is provided with legs that extend outwardly and attach to the hook portion of the attachment plate to attach the cover plate to the attachment plate.
Another example of an attachment mechanism is disclosed in U.S. Pat. No. 4,733,330 to Tanaka et al. This patent also discloses an attachment plate which is attached to an electrical box where the attachment plate has a hook-like member. A cover plate includes legs with a hooked end for hooking onto the attachment plate.
Various other arrangements have been developed for attaching a face plate to an electrical box. One type of arrangement includes spring-like members that can snap into a hole in a mounting plate or clamp onto the electrical box or opening in the wall. Examples of this type of device are disclosed in U.S. Pat. No. 1,840,582 to Hubbell, U.S. Pat. No. 3,168,612 to Sorenson, U.S. Pat. No. 3,197,549 to Good, U.S. Pat. No. 4,211,905 to Quigley, and U.S. Pat. No. 4,340,795 to Arthur.
Various other arrangements for attaching a face plate to an electrical box are disclosed in U.S. Pat. No. 3,987,928 to Mori, U.S. Pat. No. 4,631,354 to Boteler, and U.S. Pat. No. 5,180,886 to Dierenbach et al.
While the prior attachment mechanisms for attaching a face plate to a wall have generally been suitable for the intended purpose, there is a continuing need in the industry for improved attachment mechanisms for the face plate.